# Prevalence and risk factors of pre-senile lens opacities in the 1969-73 Vellore Birth Cohort

## TL;DR

This study found that nearly 14% of South Asian Indians aged 41-44 had lens opacities, with risk factors including asthma, high blood sugar, hypertension, and low vitamin D levels.

## Contribution

The study identifies novel associations between lens opacities and asthma, HbA1C, hypertension, and vitamin D levels in a young South Asian cohort.

## Key findings

- The overall prevalence of lens opacities was 13.8% in the cohort.
- Nuclear cataracts were the most common type (59.1%).
- Asthma, higher HbA1C, hypertension, and low vitamin D levels were significant risk factors.

## Abstract

To estimate the prevalence and determine predictors of lens opacities (LO) among South Asian Indians aged 41–44 years.

This cross-sectional study included 1080 participants from the Vellore Birth Cohort, Vellore, South India. All underwent anthropometric measurements, detailed ophthalmic examination including assessment of LO by LOCS III classification and biochemical metabolic measurements. ‘Any cataract’ was defined as any opacity type with a score of >2 or evidence of cataract surgery in either eye. Data collected included information on ocular history, life-style factors, socio-economic and educational status, cooking fuel and sunlight exposure. Multivariable logistic regression analysis was used to examine the association between risk predictors and LO.

The mean age (SD) of participants was 41.8 (1.0) years; 53.8% were male and 50% were rural residents. The overall prevalence of ‘any cataract’ was 13.8% (148/1075, 95% confidence interval (CI) 11.8,16.0). The types of cataract were nuclear 59.1%, cortical 16.9%, posterior subcapsular 4.1%, mixed cataracts 18.9% and pseudophakia 0.7%. Increased risk for LO was observed with a history of asthma (OR 4.51; 95% CI 2.1, 9.7), HbA1C of ≥6.5% (OR 2.29; 95% CI 1.4, 3.7), hypertension (OR 1.73; 95% CI 1.1, 2.7) and, in a subgroup (n = 372), lower 25(OH) vitamin D levels (≤20 ng/dL)(OR 5.56; 95% CI 2.3, 13.2).

The high prevalence of LO at a relatively young age in South Asian Indians suggests earlier onset of ageing. History of asthma, higher HbA1C, hypertension and lower 25(OH) vitamin D levels were associated with LO.